<form class="field" method="get" action="https://www.google.com/search">
    <div class="control has-icons-right">
        <input class="input" type="search" placeholder="Search" name="q">
        <span class="icon is-small is-right">
            <i class="fas fa-search"></i>
        </span>
    </div>
    <input type="hidden" name="sitesearch" value="haslab.org">
</form>